Question
I'm using Entity Framework 6.1 code-first and my domain model is below.
class Item
{
[Index]
public string CreatedBy { set; get; }
}
When I use update-database for migration, I get the following error. However as far as I researched [Index] should work as annotation to string.
Column 'CreatedBy' in table 'dbo.Items' is of a type that is invalid for use as a key column in an index.
Accepted Answer
Usually you get this error when you use a VARCHAR(Max) try using:
[Column(TypeName = "VARCHAR")]
[StringLength(n)]
[Index]
public string CreatedBy { set; get; }
where n is between 1 and 450.
Popular Answer
If you use EntityTypeConfiguration aka mappings :
public class MyPocoEntitiyTypeConfig<T> : EntityTypeConfiguration<T> where T:class
{
}
public class MyPocoEnt
{
public virtual string MyProp { get; set; }
}
public class MyPocoEntMapping : MyPocoEntitiyTypeConfig<MyPocoEnt>
{
public MyPocoEntMapping()
{
Property(x => x.MyProp).HasMaxLength(300);
Property(x => x.MyProp).HasColumnAnnotation("Index", new IndexAnnotation(new IndexAttribute("MyProp") { IsUnique = true }));
}
}
}
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